In the cleaning of the inner wall of tube, such as condenser tubes, in power plants, to improve the efficiency of heat transfer therethrough, a resilient scraping tool is inserted into an open end of the tube and a pressurized fluid is charged to the open end of the tube to propel the scraping tool through the tube. During passage through the tube, the scraping tool scrapes deposits from the inner wall of the tube and discharges the deposits from the other end of the tube. Such tube cleaners have been used extensively and examples of typical such tube cleaners are shown, for example, in U.S. Pat. No. 2,170,997; U.S. Pat. No. 2,418,509; U.S. Pat. No. 2,734,208, and U.S. Pat. No. 4,281,432. These tube cleaners use scraping elements that are spaced along a shaft, with scraping blades of adjacent scraping elements offset from each other so that the deposits on the inner tube wall are scraped away along the entire 360.degree. inner circumference thereof. The scraper elements, with the scraper blades, are usually formed from steel and are flexible enough to be inserted into the open end of a tube while making contact with and removing deposits from the tube wall upon passage through the tube.
It is an object of the present invention to provide a tube cleaner which is more easily inserted into an open end of a tube to be cleaned.
It is another object of the present invention to provide a tube cleaner which is more easily inserted into an open end of a tube to be cleaned, which tube cleaner is a composite tube cleaner formed primarily of metal but which has a plastic sheath over the scraping elements to prevent metal-to-metal contact during passage of the tube cleaner through a tube.